The blasting procedure used to create the Canadian channel resulted in considerable rock debris remaining in the vicinity of the waterway. Rock debris accumulated in the shipping channel. While proceeding in the middle of the channel, the ALGOLAKE contacted an accumulation of rock debris which was sufficiently large to ground the vessel.Findings The blasting procedure used to create the Canadian channel resulted in considerable rock debris remaining in the vicinity of the waterway. Rock debris accumulated in the shipping channel. While proceeding in the middle of the channel, the ALGOLAKE contacted an accumulation of rock debris which was sufficiently large to ground the vessel. The ALGOLAKE was brought to a stop and sustained significant damage to her hull when she contacted rock debris in the centre of the Canadian channel. Natural, and vessel induced, degradation of the channel sides and ice-breaking operations likely contributed to the accumulation of rock debris in the channelCauses and Contributing Factors The ALGOLAKE was brought to a stop and sustained significant damage to her hull when she contacted rock debris in the centre of the Canadian channel. Natural, and vessel induced, degradation of the channel sides and ice-breaking operations likely contributed to the accumulation of rock debris in the channel